His hobby is collecting loose stones.

This rock has been here for hundreds of years.

I can't forget the impression when I ate kaiseki for the first time.

Numerical analysis is a branch of mathematics that studies techniques and theories for solving mathematical problems numerically.

He is majoring in analysis at university.

Complex analysis is a branch of mathematics that studies functions of complex numbers.

He is an expert in harmonic analysis.

He is an expert in petrology and is in charge of geology lectures.

This beautiful apophyllite is part of my treasure collection.

I spent the summer vacation with my relatives.